Pressure reservoir with fabric bag



Jan. 16, 1934. w. A. DEL MAR 1,944,005

PRESSURE RESERVOIR WITH FABRIC 356 Filed Feb. 21, 1935 INVENTOR WilliamA. Del Mar ATTORNEY Patented Jan. 16, 193 4 PRESSURE RESERVOIR WITHFABRIC BAG William A. Del ar, Greenwich, 001111., assignor to HabirshawCable and Wire Corporation, New York, N. Y., a corporation of New YorkApplication February 21, 1933. Serial No. 657,829 3 Claims. ,(01.13'i-71) My invention relates to improvements in pressure reservoirs foroil filled cable systems and more particularly to systems conveying highvoltages under ground. During normal operation such cables undergo atemperature cycle due to the variations of current which they are calledupon to transmit. The oil, therefore, expands or contracts in volume andby means of suitable channels provided in the cable such oil may beallowed to flow in and out. of the cable at the ends or joints. Withthis class of cable it is customary to provide reservoirs at the ends orjoints to receive thesurplus oil during periods of high temperatures inthe cable and hold the oil until periods of low temperature occur in thecable when the oil contracts.

Where reservoirs can be located at suitable elevations above the cables,and connected therewith, constant pressure in the reservoirs and cablesis easily maintained due to the constancy of the gravity head. Where,however, elevated reservoirs cannot be maintained it has been commonpractice to use compressed-gas in the reservoirs. In such cases thereservoirs usually comprise two parts, one forthe oil of the cablesystem, the other for gas, the oil and gas being sepa: rated from eachother bysuitable pressure transmitting partitions.

In these pressure reservoirs .the "expansion chambers are generally madewith a flexible metallic wall between the oil and the pressureregulating gas.

Experience with such walls, whether made as bellows or diaphragms,indicates that the fatigue of the metal leads to its early cracking inservice. I have, therefore, used as a substitute, oil-impervious fabricand have found that it has a very satisfactory life.

In order to obtain the best operating life, however, I have found thatthree features of construction are of importance.

First, the operation of the fabric with oil on both sides, and

Second, the use of a cylinder of flexible fabric attached at both endsto hard discs, preferably of metal.

Third, the fastening of the cylinder to each of the discs by meansof twopressure rings, one of which serves to press on the other, which iswedge-shaped in cross-section. By virtue of this pressure, the fabric isheld in oil-tight andgastight relation with the discs.

The foregoing and other features of my invention will now be describedin connection with the accompanying drawing, forming part of thisspecification, in which I have represented my pressure reservoir withfabric bag in its preferred form, after which I shall point out moreparticularly in the claims those features which I believe to be new andof my own invention.

In the drawing:

Figure 1 is a vertical cross-section through a pressure reservoir or gaschamber in which my expansion-chamber is assembled.

Figure 2is a vertical cross-section through my expansion chamber.

Figure 3 is a top view of my expansion chamber as shown in Figure 2.

Figure 4 is an enlarged section through corner 44 of Figure 3.

Figure 5 is a diagrammatic sketch showing my pressure regulator inrelation to the cable in a transmission system.

In Figure 5 I have illustrated diagrammatically an oil filled cablesystem in which the high tension cable 10 mainly located underground, is

shown in several lengths being connected by joints llwithin manholes 12of well known construction. The outermost cable lengths are shownconnected with terminators 13 in the usual ing oil in the well known wayto a. desired extent that the oil will be within the expansion chamber'15;. of my reservoir or gas chamber 14.

1 My expansion chamber. 15 shown in detail in Figures 2, 3 and 4comprise a cylindrical fabric bag 16 cemented to two discs 17 and 18.Both these discs have sloping edges 19 as shown in the enlarged detailin Figure 4. A ring 20 provided with a sloping inner edge 21complementary to the sloping edge 19 is pushed down over the bag.

Another ring 22 is then secured to the discs 17 so i as to force downthe wedge ring 20 and hold the fabric 16 tightly against the disc 17.The disc 17, which asshown in Figure 2 is the lower one,

has a suitable oil outlet 30 connecting with the cable system as shownin Figure 5. Feet 31 are provided on the lower disc 17.

This assembly is then installed within a gas chamber or metal tank 14and sufiicient oil 40 is placed within the tank to keep the assemblycovered. The object of this oil is three fold.

1. To keep the fabric bag out of contact with air or gas which wouldtend to dry it and allow its surface to crack.

2. To afford a medium for operating a calibrated level glass 42 toindicate the height of oil in the fabric bag.

3. To reduce the difi'usion of gas or air through the fabric.

I have found it advantageous to use the above described'apparatus inconjunction with a gas adsorbent material 43 for the purpose of reducingthe volume of gas required to keep pressure within the desired limits.

I wish it distinctly understood that my pressure reservoir with fabricbag herein described and illustrated is in the form in which I desire toconstruct it and that changes or variations may be made as may beconvenient or desirable without departing from the salient features ofmy invention and I therefore intend the following claims to cover suchmodifications as naturally fall within the lines of invention.

I claim:

1. A variable capacity reservoir for feeding oil to high tension oilfilled electric cables, said reservoir comprising a bag with flexiblefabric sides and rigid ends, and connected to the oil filled cable, anda gas chamber surrounding the reservoir containing sufficient oil tosubmerge the reservoir.

2. A variable capacity reservoir for feeding oil to high tension oilfilled electric cables, said reservoir comprising a bag with flexiblefabric sides and rigid plate ends, and rings cooperating with the platesto wedge the fabric to the discs.

3; The device of claim 2 in which the wedging ring is forced against thefabric by a clamping ring.

WILLIAM A. DEL MAR.

